rotate an image aroound a point

Question

Hi all,

I have an image which is of rectangular dimension, eg 30 x 60 pixels I want to rotate this image around the bottom center of the image, i.e i want to set the pivot in the above example as (15, 60 )pixel.

I am using a drawble and matrix to get this done, whatever i try i always end up rotating around center of the image.

Code is :

Bitmap bitmapOrg = BitmapFactory.decodeFile("/sdcard/DCIM/2010-06-01_15-32-42_821.jpg");

// float angle = (angle + 10.0f)%360.0f; if(null !=bitmapOrg) {

             int width = bitmapOrg.getWidth();
             int height = bitmapOrg.getHeight();
             int newWidth = 15;
             int newHeight = 15;

             // calculate the scale - in this case = 0.4f
             float scaleWidth = ((float) newWidth) / width;
             float scaleHeight = ((float) newHeight) / height;

/* Canvas c = new Canvas(bitmapOrg); float px = ; float py; c.rotate(angle, px, py)*/

             // createa matrix for the manipulation
             Matrix matrix = new Matrix();
             // resize the bit map
             matrix.postScale(scaleWidth, scaleHeight);
             // rotate the Bitmap

// matrix.postRotate(45);

             // recreate the new Bitmap
             Bitmap resizedBitmap = Bitmap.createBitmap(bitmapOrg, 0, 0, 
                               width, height, matrix, true); 

             // make a Drawable from Bitmap to allow to set the BitMap 
             // to the ImageView, ImageButton or what ever
             BitmapDrawable bmd = new BitmapDrawable(resizedBitmap);

             ImageView imageView = new ImageView(this);

             // set the Drawable on the ImageView
             imageView.setImageDrawable(bmd);

             // center the Image
             imageView.setScaleType(ScaleType.CENTER);

// imageView.layout(100, 300, 0, 0); // linLayout.addView(imageView);

             // add ImageView to the Layout
             linLayout.addView(imageView, 
                new AbsoluteLayout.LayoutParams(
                           LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 10, 30
                     )
             );

can anyone let me know how to get this rectified?

Answer 1

Are you translating to the point you want to rotate around before doing the rotation?

Check out this resource: http://blogs.sonyericsson.com/developerworld/2010/05/31/android-tutorial-making-your-own-3d-list-part-2/